1. Field of the Invention
The present invention relates to a tag device storing information relating to, e.g., the kind and cost of an article of commerce, and for transmitting a signal based on the information in response to an electromagnetic wave received from an interrogator, and a method of producing the same.
2. Description of the Background Art
EP Publication 0 585 132 A1, for example, discloses a transponder of the type receiving an electromagnetic wave from an interrogator with antennas, causing its response circuit to output information in response to the received wave, and sending the information to the interrogator via the antennas. Power supply for the response circuit is implemented by the power of the received electromagnetic wave. When the transponder receives the electromagnetic wave from the interrogator with its antennas, a power supply circuit transforms the power of the received wave to DC power and feeds it to the response circuit, thereby enabling it. The response circuit demodulates a signal received from the interrogator, analyzes it, and then outputs information stored in the response circuit. The output of the response circuit is routed through a coupling capacitor to the antennas. As a result, the information is transmitted to the interrogator via the antennas.
The response circuit and power supply circuit are formed on a semiconductor chip in the form of a generally flat integrated circuit (IC). The IC is connected to the antennas by wires. Each of the antennas also has a generally flat configuration and and extends outward in a plane containing the flat IC. The entire IC including the antennas is sandwiched between two packings at its opposite major surfaces and sealed thereby. The packings are each formed of resin and also provided with a flat configuration. The resulting assembly constitutes a tag device which may be attached to, e.g., an article of commerce in order to send information to an interrogator, as stated earlier.
The conventional tag device described above has some problems left unsolved, as follows. The wires and antennas or the wires and connection terminals of the IC are connected by wire bonding. Wire bonding is apt to result in defective connection due to shocks and impacts which often act on the tag on the production line and at the time of use. Moreover, wire bonding needs high accuracy and thereby complicates the production steps.